The domestic readymade garment sector is booming, and garment processing has emerged as one of the important production routes towards meeting quick changing demands of the fashion market. The spread of denim culture, all over the world brought with it a trend of fast changing fashions. One after another, several washes were introduced such as stone wash, acid wash, moon wash, monkey wash, show wash, frosted wash, white wash, mud wash, etc. Over the last 10 years, India has probably seen the most dramatic and exciting changes in the washing of denim garments.
The denim fabrics are processed for desizing, stonewashing, bleaching processes and can then be further processed for different colour depth. In case of ice wash more than half the dye is removed during washing. Use of lighter shade fabric will help to cut the process time, chemical consumption, effluent load and also will help the garment processor to process garment more economically and with minimum faults.
Desizing: Traditional desizing is performed by using acid or oxidative desizing agents which is associated with many drawbacks and limitations. The drawbacks associated with traditional desizing is that due to uncontrolled and nonspecific reaction, the cellulose material gets damaged and looses strength. Desizing consumes high energy and water. Desizing using acid treatment is expensive and has the hazards of environmental pollution. Environmental regulations have put intense pressure on the textiles industry to generate less pollution. Treating the wastewater and its disposal by neutralizing the acid increases the production costs for a pair of jeans.
Stonewashing/Biofading: In traditional washing process, volcanic rocks or pumice stones are added to the garments during washing as abradant. Due to ring dyeing and heavy abrasion, fading is more apparent but less uniform. The degree of colour fading depends on the garment to stone ratio, washing time, size of stones, material to liquor ratio and load of garments. Normally after desizing, stone wash process starts with pumice stone addition in rotary drum type garment washer. Process time varies from 60-120 mins. Stone wash effect is one of the oldest but highly demanded washing effects. Stone wash process gives “used” look or “vintage” on the garments, because of varying degree of abrasion in the area such as waistband, pocket, seam and body. There are many limitations and drawbacks associated with stone washing process. Some of the commonly observed drawbacks are that, the abrasion process is difficult to control, the desired look of the fabric (denim) is not achieved, possibility of damage being caused to the fabric and metal buttons and rivets on the denims, possibility of damage to the drum of the washing machine.
Bleaching: In this process, a strong oxidative bleaching agent such as sodium hypochlorite or KMnO4 (potassium permanganate) is added during the washing with or without stone addition. Discoloration is usually more apparent depending on the strength of the bleach liquor quantity, temperature and treatment time. Intensive research is underway for the development of sodium hypochlorite bleaching alternative eg, glucose bleaching, bleaching with sulphanic acid derivatives, and recently with laccase (enzyme). Laccase enzyme belongs to the oxidoreductase group. Laccase's oxidative effect is complex, it does not work independently. A mediator is necessary and a chemical mediator is employed between enzyme and indigo and the process using laccase enzyme has to be strictly followed at acidic ph (between 4.5-5) and temperature of 58 to 60° C.
U.S. Pat. No. 6,015,707 discloses novel compositions of neutral and/or alkaline cellulase and methods for obtaining neutral and/or alkaline cellulase compositions from Chrysosporium cultures, in particular Chrysosporium lucknowense. These neutral and/or alkaline cellulase compositions can be used in a variety of processes including stone washing of clothing, detergent processes, deinking and biobleaching of paper & pulp and treatment of waste streams.
U.S. Pat. No. 5,908,472 discloses a process for providing an abraded look with a reduced strength loss in dyed fabric comprising (a) contacting, in an aqueous medium, a dyed fabric with a cellulase in a concentration corresponding to 0.01-250 mu g of enzyme protein per g of fabric; and (b) simultaneously or subsequently treating the fabric with a phenol oxidizing enzyme and an enhancing agent.
WO2006032724 discloses novel laccase enzymes obtainable from the strains of the genus Thielavia or from the strains of the genus Chaetomium. The invention relates also to nucleic acid sequences encoding the enzymes, recombinant hosts into which the nucleic acid sequences have been introduced and to methods for the production of the enzymes in recombinant hosts. The enzymes of the invention are suitable for several applications, for example for treating denim and for strain removal.
WO03016615 discloses methods for enzymatic decolorization (bleaching) and dyeing, preferably overdyeing, of a textile material in a single bath process in which the decolorization and dyeing processes are performed in the same aqueous bath.
US2006063246 discloses a novel laccase enzyme obtainable from the strains of genus Thielavia. The invention relates also to the nucleic acid sequence encoding the enzyme, a recombinant host into which the nucleic acid sequence has been introduced and a method for the production of the enzyme in a recombinant host. The enzyme of the invention is suitable for several applications, in particular for increasing the lightness of denim.
US2003040455 discloses a process for removal of excess disperse dye from printed or dyed textile material, comprising treatment with a rinse liquor comprising at least one enzyme selected from the group consisting of enzymes exhibiting peroxidase activity or laccase activity, an oxidation agent, and at least one mediator.
WO9807816 discloses detergent compositions comprising a source of hydrogen peroxide, optionally a bleach activator and an antibody to control the hydrogen peroxide bleach deactivation due to the presence of donor:hydrogen peroxide oxido-reductase enzyme, especially catalase enzyme.
EP0603931 discloses compositions comprising 1-60% organic surfactant; 1-40% detergent builder; 0.1-20% glucose; 5-5000 U/g of compsn. of glucose oxidase; an H2O-soluble source of Cu(2+) and/or Ag(+) (to provide 0.1-100 ppm of Ag(+) and 20-200 ppm Cu(2+)); a catalyst capable of catalysing the bleaching effect of hydrogen peroxide; and at least 5% water.
Therefore, in view of the aforementioned drawbacks associated with prior art compositions for bleaching of fabrics, it is apparent that there exists a need for compositions which are effective and has customer friendly applications.